DESCRIPTION: The MRL/lpr (Lupus) mouse will be used to investigate autoimmune disease in the inner ear. This mutant mouse develops elevations in evoked potential thresholds and cochlear pathology-mediated by autoantibodies deposit in the stria vascularis that do not evoke a classical inflammatory response. This study proposes to use immunohistologic and electron microscopic technique to elucidate the presence and type of antibodies, to document the presence or absence of a vasoactive complement component, and to determine the location of antibody binding within the cochlea. Electrophysiological and immunohistological techniques will be used to evaluate the consequences of antibody mediated strial degeneration on endocochlear potential and sodium, potassium-ATPase levels respectively. The ultimate goals are to identify the idiotypes of the offending antibodies, to develop a diagnostic assay for this form of autoimmune inner ear disease and to develop specific treatment regimen that can be used to prevent or reverse the cochlear pathology in this form of autoimmune inner ear disease.